Meadow Pipit

Many once common farmland birds, like the pipits & wagtails migrate to the coast in the winter, where it's easier for them to find sustenance on the shoreline.
As they don't eat berries & seeds they need live invertebrates, so when the farmland gets cold & their regular food dives deep in the soil they are often seen turning seaweed & pebbles to catch sandhoppers & the like.